Method for producing molded pulp articles



Jan.A 19, 1965 R. F. REIFERS ETAL 3,166,467

METHOD Foa PRoDUcING MOLDED PULP ARTICLES Original Filed Oct. 5, 1959 8Sheecs-Sheeil 1 INVENTORS Richard E Reifers Henry A. Lord ATTORNEY Jan.19, 1965 R. F. RElFERs ETAL 3,166,467

METHOD FOR PRODUCING MOLDED PULP ARTICLES @riginal Filed Oct. 5, 1959 8Sheets-Sheetl 2 INVENTORS Richard E Reifers Henry A.Lord

' ATTORNEY Jan. 1'9, 1965 R. F. REIFERS ETAL 4METHOD FOR PRoDucINGMOLDED PULP ARTICLES 8 Sheets-SheetI 5 Original Filed Oct. 5, 1959INVENTORS ichard E Refers Henry A.Lord

Huw. 72"@ 6ft/S' ATTORNEY Jan. 19, 1965 R. F. RElFERs ETAL 3,166,467

METHOD FDR PRoDucING MOLDED PULP ARTICLES original Filed oct. 5, 1959 ssheets-sheet 4 INVENToRs Richard F'. Reifers Henry A. Lord ATTORNEY Jan.19, 1965 R. F. REIFERS ETAL 3,166,467

METHOD Foa PRDDUCING MOLDED PULP ARTICLES Original Filed Oct. 5, 1959FIG. I6

FIG. I5

INVENTORS Richard E Refers Henry A. Lord 57,?!- 'QZ /.ocks

ATTORNEY Jan. 19, 1965 R. F. REIFERS ETAI. 3,155,467

METHOD lFOR PRoDucING MOLDED PULP ARTICLES Original Filed Oct. 5, 1959 8Sheets-Sheet 6 mvELrroRsv Richard E Refers 8 Henry A. Lord DY H9194 f2Zoc/es ATTORNEY Jan. 19, 1965 R. F. REIFERS ETAL 3,166,467

METHOD FOR PRODOOING MOLDED PULP ARTICLES Original Filed Oct. 5', 1959 8Sheets-Sheet 7 lOl FIG.23

INVENTORS Richard E Reifers &

Hen ry A. Lord /l/P l). geeks ATTORNEY Jan, 19, 1965 R. F. RElFr-:RsETAL 3,166,467

METHOD FOR PRODUCING MOLDED PULP ARTICLES original Filed oct. 5, 1959 ssheets-sheet s lllllm Il *i "Il" QL,

'INVENTORS Richard F. Reifers 8 Henry A. Lord BY MRL 7200A@ ATTORNEYUnited States Patent O v. 1959. This application Oct. 18, 1962, Ser. No.231,435

V Claims. (Cl. 162-223) The present invention relates to an egg cartonor similar article made of molded pulp and a process and apparatus formaking the same.

This application is a continuation of applicants copending applicationSerial No. 844,438, led October 5, 1959, nowA abandoned.

In the art of making `articles of molded pulp, there are threewell-known processes.

In the firstV process, the article is formed by ed onto a mold that hassuction applied to one side thereof and is immersed in a slurry that ismade up of wood and/ or paper tibersrand water, theibers being sucked upby the suction applied to the mold'and held by a screen thereon that isin the shape of thearticle to be made; the water passes throughl thescreen and is exhausted. From the mold, the article is transferred inthe first process to a supportthat is generally planar and passesthrough a heating means, such as an oven. This isV known as tree drying.Where a higher quality product vis desired, the freedried article may be'hot pressed between mating pressing dies, and this may or may not'beaccompanied by a spraying of the article. V j

ln a second well-known process, the article is molded or beingmoldformed `as above stated,` butis transferred after being molded ontoa form and it is on this form that it'passes through the oven or otherlheating means; the form may or may not be heated itself either inaddition to or asy a lsubstitutefior the oventype heatingmeans. .Afterthe 'd ryingstep,y the article is transferredtomating pressing dies asabove described. This process is known as the form drying process. 1 y

Inl the third process, two articles are formed on.- separate molds andthese articles are `then brought together and laminated,fso that theresultant article is laminated from the two molded articles.v VInthisprocess, in which form drying isppreferably used, the compe'site orlaminated article is pressed betweenimaleiand female `heated dies. l

It is understood ingthe art `that free drying gives the most warpage,that form. drying considerably reduces the warpage and that hotpressingsu'bstantially eliminates all warpage and'lrestoresthe articleto the form andshape that it had whenoriginallymolded.A

In all of these Processes, and 1n variations `of *themV known to'the.art, theafterlpressi'ng, which is the pressing that takes placeVaftergthe molding or forming of the article,

is for the purpose of restoring the varticles shape to that itoriginally had and hence was recognized as a correcting or rectifyingstep'inf-whiclr little or no change was made in the actual configurationofthe article, such changes as were made" beinglargely for producingonly surface effects on the articles. n

In addition 'to these` 4threegenerally recognized processes, there is'alsoknowwn aiprocf'es's in which the initial molding operation isof"la.s'he"et that is thereafter formed into the desired contiguratipnpressingthe article'to the desired form; This VJis simila tothewell-known press formingof sheet metah'ahd is*a limited as to depth of.draw ofthe-articleand 'tdsi'mple geometrick shapes'.v w

`One of the primary uses of the'articles'produced-Strom '7 l 0molded'pulp is for thepackaging of fragilelarticles,4 egg cartonsjbeingone leading example; There are certain 1characteristics that are desiredfor the eggcartons that lbh? Patented Jan. 19, 1965 ICC are produced,and some of these characteristics,rat least, depend upon the process bywhich the article was made.

For example, in cartons for packaging eggs, it is desirable to have acarton that is strong and will withstand a considerable amount of torce.This is necessary in order that the carton may be handled inautomaticmachinery and may protect the eggs, or other fragile articles,from shock and other forces thatv arise during the handling of thefilled carton both in automatic closing and sealing machinery and in thetransporting of the lled carton from place to place during the'marketingoperations. In addition to the strength characteristics, the carton mustnot be hard and unyielding for if it were the eggs would be subjected toimpact shocks that would tend to cause egg breakage. Consequently, it isdesirable that those `parts ofthe carton that are in Contact with theegg or other fragile object possess aV certain amount of softness and/orresiliency so that the shocks will be cushioned and their effectmitigated to thus reduce or avoid egg breakage. ln particular, it hasbeen found that articles that are after-pressed, that is, that arepressed after the molding and drying operations, have imparted to them areduced hardness and a smooth surface. This is due to the fact that thefibers are disturbed from their original bond by the pressing along withthe reduction of original y thickness.

Because after-pressing was known Vto reduce hardness -of the carton,many workers in the art have previously ksought to provide' aconguration of carton that would ahd cushioning than was intended anddesired.

By'the process of the present invention, the conguration of the moldedarticle is changed in the after-.pressing operation. This change, whichmay conveniently be Vdesignated as a `reforming, of the article, isKVaccomplished by having after-'pressing dies of different contigu-Vration or shape, in certain parts, thanV anyof the other molds, dies orinstrumentalities that were used to initially `form the article. There-is thus obtained a carton that may have the samel or similarconfiguration tothat of a previously known carton, but whichwill havethe above noted superior cushioning ability asa result fof the formingand reforming steps VVof the present inventive process.

of an article thatV is inV production, itfis: onlynecessary with thepresent process .to make newprlessing dies and to instal-l them only inthat part of the apparatus that is saving of production time`andoverhead and otherex- Mpense.' ,y i' Y y The machinery of suctionmolds or dies isvery :expensive and time consuming. A pluralityo-fsuchdies are mounted Vin sealed, longitudinallyand c'ircurnferentially` 4spaced relationv on a huge cylinder. #The-cylinder is rotated inV aslurry-of pulp bers and the dies-are periodiwhen 'immersed in the `pulpcally subjected to rvacuum slurry. i

In addition,1 it Willfbe seen that where it is'j desired to modify,within certain limits, the conguration It is not only expensive to toolup for a new shape of egg carton, but those skilled in the artappreciate that relatively thin hollow shapes are extremely diflicult toform. Sufficient draft must be provided to permit removal of a preform.Where a deep hollow shape is relatively narrow, for example, the suctiondies do not provide suicient suction holes to draw the pulp slurrytherethrough in order to form the preform without thinned out spots orholes. Thus it is well known that unless sufficient suction can beapplied at critical portions or shapes to be formed instead of forming apreform as a uniformly thick layer of pulp fibers, improperly formedareas will result.

One expedient utilized to overcome the formation failures where suctionholes are at a minimum is to keep the suction dies immersed in the pulpslurry an exceedingly long time. This of course increases productiontime and the cost of the finished article.

Cost is one of the primary concerns in pulp articles being produced,especially egg carton, since these containers are generally of thesingle use or throw-away type.

If relatively complex or intricate and diiicult-to-mold shapes areformed on suction molding apparatus, the problems of plugged-up dies andaccompanying maintenance costs increase. It is highly desirable toproduce articles with the least number of rejects and yet maintainproduction at peak eiciency.

By reforming the more intricate and complex shapes away from the suctionapparatus, the pressing dies, which aire relatively simple to machineand install, reduce plant conversion time to a bare minimum and yetprovide for article shapes and selected portions which are extremelydifiicult to produce on the suction dies.

Modification of the configuration of an egg carton finds one applicationin the manufacture of egg cartons of a size to hold very small eggsknown as the pullet size.

Pullet eggs are laid by new layers, and the season is generallyheavierin July and August, although with the recently adopted practice ofrotating flocks, seasonal increases in pullet eggs are less pronouncedthan formerly.

In order to make pullet size molded pulp egg cartons, it would have beennecessary to produce complete sets of dies and forms for the entireproduction machinery. This would take about nine months, and thusrequire considerable advance planning. The new size dies would besubstituted during a four-week changeover period, and then after a shortrun was made, a second changeover period would be required to changeback to the i original dies and forms. These changeover periods wouldyhave necessitated the machine shut down for excessive periods withresultant loss of profits. As a result of these economic limitations,production of the pullet carton was precluded.

Further, it has been found that for eggs ofv approxifrom the point ofmaximum girth, than others, and some of these longer eggs will comeintocontact with the bottom of the egg cell. Efforts have been made inthe past to support the egg by holes or thin wafer-like sections, butthe hole has been found to have a hard edge and thus to give rise tohigh local pressures on the egg', with resultant breakage, andthecontrol of quality limits of the thin sections has proven difficult, sothat there has not been provided heretofore an entirely satisfactoryconstruction of -eggcarton cell bottom.

Modification of the configuration of an egg carton finds anotherapplication vin the manufacture of egg cartons having a cellular bottomsection and a cover section with a planar top and posts to support theplanar top of the cover section. While cellular bottom sections withposts -between the cells have been provided, andv while it has beensuggested that one or more of these posts could be high enough tocontact with the underside of the top of the cover section, in practicethis latter con- `mately the same diameter, some are longer, Ameasuredstruction has not been adopted because those skilled in the art haveconsidered it impossible to achieve within the space limitationsestablished by the egg packaging industry. It may be mentionedparenthetically that the modification of an existing carton constructionby providing essentially a post resulting from an extension of theheight of the walls between the cells at their existing angle results ina post with an extremely small or pointed top. This construction is notsatisfactory because the post top tends to pene-trate the cover top,rather than support it, and furthermore it is not practical to producebecause of complex construction. Alternatively, to provide aconstruction in which the angle of taper was modified -to provide thenecessary top area would result in a construction which would not nestnor give sufcient egg room.

An object of the present invention is to provide a process for makingarticles of molded pulp that will enable the configuration Vof thearticle to be changed more rapidly and economically than in the past.

Another object of the present invention is the provision of a processthat will result in a molded pulp article that will provide greatercushioning for objects held therein.

Yet another object of the present invention is to provide a process thatfacilitates the effecting of modifications in the configuration of anarticle that is in production.

A further object of fthe present invention is to provide a process formanufacturing molded pulp egg cartons having a post supporting theplanar top of the cover thereof.

A still further object of the present invention is the provision of anapparatus for forming and reforming articles of molded pulp so as toimprove their characteristics.

Another object of the present invention is to provide an apparatus `formaking molded pulp articles that may Imay bereadily incorporated intoplants now equipped with molded pulp article-making apparatus with aminimum of time and expense.

Yet another object of the present invention is the provision of an eggcarton having improved egg cushioning characteristics.

A further object of the present invention is to provide a molded pulpegg carton that will reduce egg rattle and egg breakage. v

Another object of fthe present invention is the provision of an eggcarton that combines characteristics of high strength withcharacteristics of positively holding the egg in parts that cushion theegg against shock.

Yet another object of the` present invention is to provide an egg cartonproviding a softand gentle support for long eggs at the bottom of thecell.

Other objects and many of the attendant advantages of the presentinvention will become apparent upon consideration of the followingspecification and accompanying drawings, wherein: l

FIG. 1 shows schematically an apparatus in accordance with the inventionand capable of performing the process of the invention. v i

FIG. 2 is a cross-sectional view, with parts in elevation, of a formingdie used for forming an article in accordance with the presentinvention, with an article thereon.

FIG. 3-is an elevation of a drying form.

FIG. 4 is -a view showing, in stepped sections, ing dies in accordancewith the invention.

FIG.,4a illustrates'the relative dimensions and shapes of a portion ofan article before and after treatment in the pressing dies of FIG. '4.,

FIG. 4b is a cross-sectional View showing the pressing diesof FIG. 4pressing and reforming an article therebetween. Y f

FIG. 5 is a cross-section, takenfgenerally on line 5--5 press- 2.4 ofFIG. 22,

of FIG. 6, of the article after being reformed in .fthe dies of FIG. 4showing thearticle in a closed condition.

FIG. 6 is an unfolded, fragmentary plan view of the egg carton of FIG.5.

FIG. 7 isa fragmentary elevational view of a single egg cell of thecarton shown in FIG. 6.

FIG. S is a cross-sectional view taken Ion the line 8 8 of FIG. 7.

FIG. 9 is a fragmentary plan viewV similar to FIG. 6 of the bottomsection of another form of egg carton in accordance With the presentinvention.

FIG. 10 is a cross-sectional view taken on the line 1)- 10 of FIG. 9. i

FIG. 11 as aview similar to FIG. 10 and showing an egg in the cellthereof.

FIG.v 12 is a fragmentary planv view similar to FIG. 6 of the bottomsection of another form of egg carton in accordance with the presentinvention.

FIG. 13 is an elevational view of an egg cell of the bottom sectionshown in FIG. 12.

FIG. 14 is a cross-sectional view italien on the line 1dv14 of FIG. 13.

view similar to FIG. 6V

FIG; 19 is ajfragmentary vertical sectionl takenv sub- Y stantially onthe line I9-19 of FIG. .17;

FIG. 20 is a cross-sectional `vievf talr en on the line 2tl- 20ofFIG.19. f Y FIG. 21 is laplanzviewyof another-cell in accordance withthe present invention. i

.p Y FIG. 22 is a fragmentary plan view similar to FIG. 6 l, of anotheregg carton made in' accordance with the present invention and ona'slightly reduced-Scale.

' FIG. 23 is a cross-sectional view-taken on the 2s of F1G.22. y

FIG. 24 isla cross-sectional view taltvenvon the line 2drune as' FIG. 25is a invention.l

FIG. 26

planview'l'of an eggilat ofv the present is a cross-sectional view ofthe eggflat of FIG.

r2,5, and showing a cover Ain place thereon. Y

vReferring now to the drawings, wherein like reference characters areused `to designate like or corresponding parts throughout the`severalviews, there is shown in FIG. l a preferred apparatus forcarrying outV the process of the invention,` and there may be seenthereinrthe molding apparatus.'generallydesignated 2i?, this moldingapparatus comprising'in known manner a molding wheel 211 having on theperiphery thereof aV plurality of forming dies 22; iAtanlt'Z??containing a pulp slurry is 'positioned beneath the 'wheel 21 so thatthe forming dies 22 willbeimmersed in the slurry as thewheel 21revolves. In knownfashion, when the die 22l is immersed in the slurry,suction will be applied to the inner'side thereof to suck the slurrythrough the mold 22 so that the' pulp ner layer of fibers as comparedwith other portions, for

example, the planar top of the carton, etc. `The posts are a closed,hollow elongated formation.

,ing rejects) and the volume of the egg. cells is increased tofacilitate the accommodation of larger sized eggs withoutdisturbingrexterior dimensions of the egg cartons.

When the article has been formed on the forming die 22, it leaves theslurryand at this stage contains a great amount of water. The wetarticle A is removed from the die 22 and transferredto a drying form 26that is carried by a conveyor 27. Conveyor 27 extends through a dryingapparatus, preferably a drying oven 2e.V After traversing the oven 28,the article A is placed between The pressing and reforming vdies may bemounted as shown in FIG. 1 in a press 3@ which carries the mutuallyreciprocable mating dies 32 and 33. ri`he article' A isremoved from thedrying form 26, and at this stage, of course, it will be understood thatthe article A is formed and dried and that it usuallyfhas at this stageof its manufacture a small amount of warpage. It is transferred by knownmeans tothe press 30, and there is then effected a reciprocable movementof one or both of the dies 432' and 33 to'cause them to come together topress and reform the article A between them. v The die 22, shown best inFIG. 2, molds or forms the article A as above stated; article A is, intheexample shown, anv egg carton having a bottom section with eggreceiving cells vthat are generally concave with an upstanding button onthe cellbottonnas is well known; article A uniquely `*has posts 3d ofsufficient height .to engagel the underside of the `top of the lcoverwhen the carton is closed. vThe dryingform 26, shown in FIG. 3, is'cfthe same configuration as the die 22, and is preferably a male form, 'asshown. I v The' pressing andformingdies 32 and 33, shown in FIG. 4, haveportions thereon which Areform several parts pressingl and reformingdies.

ofthe carton bottom section. K The female die 32 has anvf'upstandingjpo'st Sb that-issimilarvto the post '34o of the dieEach'postolbv has foursidea'each of which Y vconfermato the surface ofan inclined cylinder, two such sides being shown in FIG. 4'. Y However,the angle to the vertical of the sides of post 34a of die 22 is llessthan the angle to theY vertical of the sides of post 34.5 of the femalepressing die 32. In practice, this diierence is in V the order of 21/22"The height of post Sb-is the same `as the height of post-34a, but theextent or area of the top of post 34a is greater than that of post Elib.

VThe frnale die 33 hasa generally correspondingrecess I 34e, made up offour inclinedV sides which conform to the surface of cylinders; thesides of recess Mohave, howfibers lodge on the outer surface ofthe mold,which is usually a finemeshscreen. y K Y A n Y vThe forming dies 22, secFIG. 2, include a perforated backing plate o1' base 22.5zwhich is tooled-to have the ultimate preform shape and'hasformed therein a-pluralityofl transverse suction passages 22h. The inner surface of theplate 22ais coveredrb'yI a foraminousi-sc'reenZZ.

Itl -will be` noted -thatth'e` forming die 22 includes postformingportions, 'to be later-'discussed in detailwhich Lhave relatively fewaccessible rsuction passages` 22o :at 4the area22d `of thepost. Thepaucity of suction passages at the areas 22d tends toresult in arelatively ythinever, protruding generally elliptical: blisters Edfwhich have their greatest outwardextensionat the'approximate VmidpointthereofV and are each regularly curved therefrom'. The blisters dfare inregistry withsimilarlv Vshaped areas of the article or carton A ofreduced thiclzness relative to the normal thickness of the article A.

The mannei'in which blisters Slffare formedion the carton preform isaccomplished byrneans` of blistershaped blocking-out elements (notshown) ,incorporated onfthe screen 22d, and the pulp berin theblister-forming reas will'lbuild up over the blocking-out elementsduring initialsuction deposition. Y

' After reforming, it willbe noted inx-FIGSQ 4d and4-b, l V,thethickness of 'those portions of the posts adjacent the" blisters Gifwill be greater'thanthe thickness ,ofi the olis-g ters and theindentation fwillbereversed, Le., inFIG.

4a the blisters are partially formed onnthe inner surface of the posts34 of the preform, and after reforming the blisters are on the outersurface.

The blisters 34f in the final product will comprise liber in which thebond between individual fibers has been disturbed, and this results in acushioning area which will accommodate eggs of different grades orsizes.

It will be noted that although the blister-forming portions areinitially formed thinner the post portions between adjacent blisters 34fwill be uniform in thickness along the length of the posts 34.

The posts will have sufiicient columnar strength to transmit or sustainvertical loads or shocks and yet include selected areas with uniquecushioning or supporting characteristcs.

As a result of the differences in the configuration of the forming dieand the pressing dies, during the pressing of the egg carton A, thewalls and top of the post are reformed; the pulp of the top is crowdedtogether towards the center, but the relative height of the top of thepost is unchanged. This is shown in FIG. 4a, the dashed linesillustrating the size and shape of the post 34 of the article A after itis formed and dried, and the full lines illustrating the size and shapeof the post 34 after it is reformed in the dies 32 and 33. The walls ofthe posts are reformed by having the angle thereof changed so as to beless steep, this also appearing in FIG. 4a.

As mentioned above, the carton produced by the novel method uniquely hasposts 34 of suicient height to engage the underside of the top of thecover when the carton is closed. The posts per se comprise a hollowclosed construction which must withstand vertical loading in thefinished carton, and thus must contain sutiicient fibers to afford agood base upon which the underside of the cover will rest. Known suctionmolding techniques, as mentioned above, do not provide sufficient fibersat the upper ends of the posts, i.e., in the preform.

The initially formed posts 34 of the preform A are of a size which isgreater than the corresponding post of the ultimate carton. Thisexpedient permits the side walls of the hollow post, which is closed atits top, to be bodily displaced approximately 21/2 degrees and the pulpor liber is crowded toward the center of the posts. By crowding the pulptoward the center, the posts of the finished carton gain columnarstrength, the volume of the adjacent cells is increased without a changein the exterior dimensions of the carton, and the crowding of the pulpcompensates for any thin portions at the crown or top of the posts. Thereforming technique thus provides means for ncreasing a concentration offiber at a critical area which cannot be accomplished by conventionalsuction molding techniques where especially long and relatively smalldimensioned shapes are involved.

In conventional reforming or pressing techniques where opposed surfacesof a layer of ber are pressed and grooves or embossments are formed, ifclosed hollow posts of a preform are pressed by dies from both theinside and outside by mating dies, the posts would be stretched, and anyminor faults in the post would be exaggerated or be further developed,i.e., where an excessively thin layer of fiber has been deposited. Byusing an inward compaction and reforming technique as explained above,any thin sections formed during initial molding of the carton preformposts are compensated for during the reforming step, and production timecan be decreased because if post portions are suction molded relativelythin, this discrepancy is compensated for during reforming andcompaction.

The areas of carton A registering with the blisters 34]c are alsoreformed, due to the relative shapes of the forming die 22 and thepressing dies 32 and 33, particularly pressing die 33. f

While the egg cells of the article A, as'molded on die 22, aregenerallyconcave with rounded and flat portions as shown in the patentto Cox No. 2,771,233, issued Novem- -ber 20, 1956, these cells are alsoreformed in the dies 32 and 33. In the female pressing and forming die32 utelike protrusions 36b are provided on the wall of ,the egg cellcavity thereof; these protrusions 36h are of a generally elongated teardrop shape, having downwardly tapering tails. A shallow dent 36d, ofpreferably circular contiguration, is located in the protrusion 36b,adjacent the upper end or head thereof. A corresponding flute-likeindentation 36o is provided on the mating pyramidal male part of the die33, there being a bulge 36e at the upper end thereof. Pressing die 32also has an annular protrusion 37b on the bottom of the cavity thereof,and the male die 33 has a protrusion 37C (see FIG. 4b) on the bottom ofthe mating pyramidal male part, protrusion 37C being surrounded by agroove`38.

In FIG. 4b there is shown a cross-sectional View, taken diagonallythrough an egg cell, and showing the article A being pressed andreformed in the pressing dies 32 and 33.

The blister 34f is seen pressing and reforming a side 0f a post 34, thepost 34 being thinner than normal where it is in registry with blister341. This thinness is due in part to the fact that this area was formedthinner and in part to the fact that it is pressed between the blister34]" and the underlying part of the post 34h of die 32.

The annular protrusion 37b of pressing die 32 cooperates with theprotrusion 37C and groove 38 of pressing die 33, and the protrusion 36band dent 36d cooperate with the flute-like indentation 36C and bulge36e, respectively.

The resulting article A as shown in FIG. 5 is, of course, the samearticle A that was formed on the die 22, but has been reformed in partto have fiutes 36 that extend into the egg cells of the article A, theflutes 36 having flattened upper ends 36. The molded pulp button thatwas an upstanding protrusion on the bottom of the egg cell of article AIhas been reformed into a thin wafer 39 having a surrounding pillow 39'.It will be understood that the position and dimension of wafer 39 withrespect to the cell bottom, either higher, lower, thicker or thinnerthan that shown in FIG. 5, depends upon the existence and height of theprotrusion 37b and 37C on the dies 32 and 33.

Thus, the wafer 39 may appear other than as shown in FIG. 5. The posts34 extend upwardly into engagement l with the underside of planar top`35of the integral cover section of carton A, and each side of a post 34has a thinned, generally elliptical area 34".

It will be seen that the above described apparatus and process areeffective to produce `an article that is first formed, then dried andfinally pressed and reformed so as to obtain a ldifferent configurationof the article. Not only does there result a change -in theconfiguration of the article, but more importantly there results achange in the charactenistics of that part of the article that has beenreformed. Thus it is to be understood that the reforming of the parts ofthe article that become the fintelike protrusion 36 and wafer 39 shownin FIG. 5 serves to disturb the entire body-of fibers therein and thebond between the fibers. As to the flute-like protrusions 36, the cartonbody portionas initially `formed was concave, and is reformed to aconvex configuration that is considerably softer and more yielding thanthe remaining nonreformed part of the article or carton A. Thus, thearticle or carton A reta-ins its general over-all strength but isprovided with flute-like protrusions 36 that possess completelydifferent charcteristics from the other (non-reformed) parts of thecarton in that they will yield more readily under load. The reforming ofan article `is great enough in certain instances to cause the reformed-part of the article to go to a point of opposite image; the originallyformed article may, for example, have a part that is concave a certainamount, and that is convex a like amount after reforming.

The wafer 39 and pillow 39 are also soft and yielding, and serve tocushion any long eggs that come into contact with them, and thisformation will prevent leakage in the event of breakage.

Although the apparatus shown is the preferred appara- ,6i tus forcarrying out the process, it will be understood that other apparatus mayalso be Vused and that, in general, any apparatus that first forms anarticle and then reforms it after it has dried, preferably, vissuitable. For example, the process may be carried out by an apparatus inwhich the pulp is first molded into a sheet, and then the article isinitially `formed tfrom the sheet; thereafter, the article may bereformed in accordance with the above teachings. Gther apparatus thatare suitable for'carrying out the process of the invention will beapparent to those skilled in the art, only one of the apparatus havingbeen shown in the drawings.

Referring now to FG. 6, there may be seen therein a plan view of thecarton shown in section in FIG. 5. ri`he egg carton bottom section 40 isan egg receiving section having egg receiving cells 41, each of thecells 41 having a square bottom 42, from the sides of which the lowerwall portions 43 incline upwardly and outwardly at a predetermined angleto the vertical, thereby providing a generally polygonal lower portionof the cell. The polyg- 4 onal lower wall portions 43 merge upwardlywith rounded, generally conical, upper cell portions 44, and theseVupper cell portions 44 are at a lesser angle to the vertical than thelower portions 43. The Vcell as thus de`V scribed is known in the art,and is fully described in Patent No. 2,771,233, whichv issued to l. W.Cox on November20, 1956. From each corner of the base 42 there extendsupwardly, and at an angle that is preferab'ly 15 but may be within therange of 1G-15, the

reformedconvex flutes 36. Flutes 36 have liattened upper ends 36 toprovide a cell having Vmore room `for the v egg than would be the caseotherwise. In the bottom 42 are the reformed wafers 39 and pillows 39.

FIG. 7. shows the appearance of an egg cell 41 from the outside thereof,and there may be` seen the reverse,l

or concave, side of the flutes 36, as well as the iiattened upper ends36' thereof, the fiat lower wall portions 43 and the conicalupper cellportions 44.

FIG. 8 shows the thin and. yielding egg-contacting area 34' in the post34, the posts 34 in the regions. on either side ofthe area 34 beingrelatively thick and thus having a high strength. The posts 34 aretherefore strong at the four regions where the sides of the post 34 joineach other, and consequently have good columnar strength.V There mayalso be seen in FIG. 8-the shape of the" ilutes 36 as well as theflattened end 36' of one flute 36.

The egg carton shown in FIG. 9 is generally similar to that shown inFIGS. 5 and 6, with the exception that there is not provided in thisembodiment the posts 34 that contact the underside of the.y cover of thecarton. Instead, the posts are of normal height, i.e., they extend onlyas high as the highest part of the remainder of the bottom section.Thus, the carton of FIG. 9 more utes 36 therein, and as shown in FIG.1l, will deflectand depress the reformed iiute 36 because of thesoftness and cushioning ability thereof. The cushioning ability of thereformed flute 36 is such that an egg may be safely dropped into `thecell 41, as is done in automatic egg carton iilling machinery, withoutdanger of egg breakage. With the reformed flute, each cell actsindependently, so that a heavier egg in one cell will cause the reformedilutes thereof to deliect without having any effect on the eggs inadjacent cells, or the adjacent cells themselves.

In the copending application -of Henry A. Lord and Harold S. Crane,Serial No. 669,362, tiled July 1, 1957, which matured intol UnitedStates Letters Patent 2,924,- 358 on February 9, 1960 there is describedan egg carton having egg receiving cells that are generally triangular,or trapezoidal, and such a carton has been shown in FIG. 12, reformed inaccordance with the present invention. Thus, there may be seen in FIG.12 a lower section Sil of an egg carton, section having a plurality ofcells 51 each of which includes a horizontal base 52 that issubstantially in the shape ofan equilateral triangle, or

` other.l Abovethewalls 53, 54 and 5S there are upper wall portions 53A,54A Vand 55A that extend upwardly from the top of their respective lowerwalls and at a lesser angle to the vertical. Extending between the wallsabove described and as shown onthe drawing, thereare auxiliary walls 56,57 -and 58, and these auxiliarywalls are of substantially the same angleof inclination as the upper wall portions 53A, 54A and 55A and extendupwardly from v4the apices of the triangular base 52, increasing inWidth from said apices. v

Y Flutes 53B, 54B and 55B are respondingy lower and upper walls 53, 53A,54, 54A, and 5s, 55A. f 1 v The appearance of typical ilute'SftB isshown in FIG. 13, andthe protrusion of the iiutes 53B,54B an'dSSB intothe cell 51 is clearly shown in FIG. 14. FIG. 15V

v shows in dotted lines the position of the walls S3, v53A closelyresembles that carton which is disclosed in Cox 'y Patent No. 2,771,233.Thecartonof FIG. 9, as will be apparent, is one which is reformed from acarton that is moldedin accordance with the Cox patent, and there-` ifore does not require the producdon of or changeover to new molding diesin a plant having ysuch dies for the production of the carton ofthe Coxpatent.`

The carton of FIG. 9 has a bottom eggreceiving section 45 with egg cells4l. that arethesame as egg cells 4i ofthe bottom sectionshown in FIG. 6.Thus, there is shown inFiG.` 9 .the bottom 42. withwafer 39 and pillow39', the lower wall Vportions 43 and the upper cell portions 44. v

The utes 36 are of teardrop shape `at their` upper yends to facilitatethe reforming of the material, and have a relatively large radius. Theradius is important from consideration of hexibility, flexingof thematerial and `the convergence of the ilutes at the cell junctures.

In FIG. 10 there `may be seenthe-egg cell 41 having 7 the twoutes 36therein in full line position, the portions that formed the tintes 36before the reforming of the carton bottom-section 45 being shown indotted lines. Y

and 54, 54A after the carton 50 is initially formed andl shows in fulllines the reformed flutes 53B and `54B, in accordance with-theinvention.

In FIG. 16 there may be seen cell `51 having the reformed llutes 53B and54B, and it may be clearly seen that these reformed ilutes havedeflected in order to accommodate and receivel in a cushioning mannerthe egg therein. e f

In FIG. 17 there is shown a lower section 60. of an egg carton having aplurality of cells 61 each of which includes a horizontal base 62 thatis substantially in the shape of a trapezoid. Extending Vupwardly fromeachv ofthe four edges of cell base 62 of each cell is ak cell wall, thefour walls being designated 63, 64, 65, 66. As in the carton 56 of FIGS.l2, 13V and 14, each of these walls extends upwardly -towards the top ofthe carton bottom section, and as in carton 5 0 each of the cellwallsVinclines upwardly'andoutwardly from the base 62 and diverges from eachother wall.

Reformed tintes 67, 68,69 and 7 6 may be seen'irfthe upper parts of thecells 61. In -thisembodiment no flute is adjacent the hinge 71, asresults with the'placeme'nt shown in FIGS. l2, 13 and 14.

- FIG. 18 illustrates the appearance of margins of the carton bottomsection 60. FIG. 19 shows reformed from the cory j the cell 61, inexterior elevation, and showing'the reformed flutes 63v and 69, whichare those'iiutes that are closest to the outer aieaae? the reformedflutes 67 and 70 that are closer to the interior of bottom section 60,these two views showing `the relative spacing of these pairs of reformedflutes. As

is best shown in FIG. 19, the flutes 67 and 70, which are in the wallsof the posts of bottom section 60, extend from adjacent the tops of theposts and terminate well above the bottom 62. These flutes 67 and 70 arethus relatively short.

In FIG. 20, there may be seen the convex reformed flutes 67, 68, 69 and70, and the straight walls 63, 64, 65 and 66 of the cell 61therebetween.

FIG. 21 shows a cell Si! that is generally similar to the cell 61, buthas only two flutes 87 and 9i) therein, corresponding to the flutes 67and 70 of the cell 61. This is a simpler cell which provides suitablecushioning support for the eggs.

In FIGS. 22 and 23 there is shown a carton bottom section 100 similar tothe carton bottom section 69 of FIG. 17, in that the cells 101 of thiscarton are of the generally triangular shape of the cells 61. Thus, thecells 101 may be seen to comprise a generally triangular bottom 192 withthe three main diverging and inclined walls 163, 164 and 165 risingtherefrom. The walls 104 are parts of a reformed post 166 which has aheight sutlicient to contact and support the underside of the cartoncover, the height of post 106 being clearly shown in FIG. 23.

The underside of walls 104 and 165 of the posts 106 are thin in the areaindicated at 107. The thinned areas 157 are of generally tear drop shapeand are positioned laterally intermediately of the walls 164 and 165.They extend from near the top of walls 104 and 195 to adjacent the levelof the cell bottoms 102, and therefore are engaged by eggs placed in thecells. Because of the thinness of the areas 167, the walls ft and 10Swill deflect under the weight of an egg, and thus will yieldinglycushion the egg. These areas are similar to the thinned areas 3d of thecarton A, shown in FIGS. 5 to 9.

The triangular cell 101 may be utilized in an egg flat for holdingthirty-six eggs, as is shown in FIG. 25, wherein there may be seen thecells 161 each having a bottom 162 and the walls 103, 164 and 135, thelatter forming the posts 106. There are three rows of posts 1%, and in`addition there are two rows of posts 19S, one row of posts 11i-S lyingbetween each two rows of the posts 166.

The walls 194 and 165 of the post 106 of the egg flat may also have thethinned areas 107, as is 'shown in FIG.

The egg flat of FIGS. and 26 may be divided into groups of cells witheach group containing only a few cells. Thus, each group may contain onedozen eggs, or a half-dozen eggs. Where a dozen eggs is to be sold, theegg flat may be cut along a line of posts 198, and the cover 109 cutcorrespondingly.

There has been provided apparatus and process for making a greatlyimproved molded pulp article, particularly a molded pulp egg carton. Inaccordance with the apparatus and process of the invention, an articleis first or initially formed and then a part of the article is reformedand this part obtains thereby a softness and resiliency that it did notinitially possess and which is not possessed by articles or cartons thatare initially formed in the same configuration as the reformed articleor carton hereof. There has also been provided superior egg cartons thathave 'reformed flutes extending or protruding into the cell space toreceive an egg in a secure manner and yet which cushion` the egg toreduce egg rattle and egg breakage. Further, bythe process of thepresent invention, it is possible for the first time to manufacturemolded pulp y egg cartons in which a past extends upwardly from a bot-The posts 106 and 168 will engage with and support the underside of thetop 11d of the cover 109.

the invention and therefore the invention is not limited to what isshown in the drawings and described in the specilication but only asindicated in the appended claims.

What is claimed is:

1. The method of producing a molded pulp egg carton having a cellularbottom tray including a peripheral margin integral and hingedlyconnected along one edge to a dished cover having a planar top panel anddepending sides engageable on the peripheral margin of said cellularbottom tray, and wherein a plurality of cells are formed aboutvertically extending hollow post integral with said cellular bottom trayand projecting vertically above the peripheral margin thereof, saidmethod comprising the following steps:

(a) sucking a pulp fiber preform formation for a pulp slurry onto aforaminous die of the general shape and contour of said egg cartonincluding said hollow-post forming portions;

(b) removing said pulp liber preform formation from said foraminous die;

(c) drying said pulp fiber preform formation after having removed itfrom said foraminous die; and

(d) pressing said pulp liber preform formation between mated pressingdies which include male and female hollow-post accommodating portionssmaller in horizontal cross section near the top thereof than thecorresponding horizontal cross section of said foraininous die, andcompacting and reforming the pulp fiber at the top of said hollow-postportion on said preform and reducing the outer and inner margins of atransverse section near the top of said hollowpost forming portion.

2. The method as claimed in claim l including:

(e) forming the hollow-post forming portion of said pulp liber preformat a relatively steep angle with respect to a horizontal plane passingthrough the bottom of said cellular bottom tray and with a transversecross section facilitating removal of the pulp fiber preform from saidforaminous die;

(f) reforming said hollow-post portion while pressing it inwardly fromall sides to an angle differing from that initially formed on saidforaminous die to increase the capacity of the egg cells of the cartonand facilitating nesting and denesting thereof.

3. The method as claimed in claim 1 including:

(e) forming on said hollow like post forming portions intermediatediscrete areas having a fiber consistency differing from that ofadjacent portions surrounding said discrete areas, while sucking saidpulp fiber preform onto said foraminous die; and

(f) reforming and pressing said discrete areas to a thickness thinnerthan said surrounding areas while reforming said hollow post formingportions with a smaller horizontal cross sectional area.

4. The method as claimed in claim 3 including:

(g) maintaining said hollow post-forming portion at a lengthsubstantially equal to that at which it was initially formed on saidforaminous die while reforming and compacting said post-forming portioninwardly and while reforming and pressing said discrete areas.

5. The method of forming a molded pulp egg carton of the characterhaving a cellular tray integrally connected to a dished cover andwherein a plurality of cells are grouped about a hollow post, saidmethod comprising the following steps:

(a) sucking a pulp fiber preform formation from a pulp slurry onto aforaminous die of the general .shape and contour of said egg carton andincluding a hollow-post forming portion;

(b) removing said pulp fiber formation from said foraminous die andeffecting drying thereof;

(c) pressing said pulp fiber formation between mated pressing diesincluding a hollow-post forming portion and reducing ythe outer andinner margins of its transverse section near the top thereof;

crete areas having a thickness differing yfrom that 0f adjacentportions, while sucking said pulp ber preform; i

(e) reforming and pressing Vsaid discrete area while reforming saidhollow-post forming portion with a smaller horizontal sec-tional area;

(f) maintaining said hollow post lengthat substantially the-length whichit was initially formed on said foraminous die While reforming andcompacting said (d) forming on said hollow-post forming portions discent )portionsl of said hollow post forming portion; v

and

(h) inwardly pressing said discrete areas to dispose the outer surfacethereof below the outer surface of said adjacent portions Whilereforming said hollow post-forming portion.

References Cited in the le of this patent UNITED STATES PATENTS NewsomJune 6, 1939 2,924,368 Lord Feb. 9, `1960

1. THE METHOD OF PRODUCING A MOLDED PULP EGG CARTON HAVING A CELLULARBOTTOM TRAY INCLUDING A PERIPHERAL MARGIN INTEGRAL AND HINGEDLYCONNECTED ALONG ONE EDGE TO A DISHED COVER HAVING A PLANAR TOP PANEL ANDDEPENDING SIDES ENGAGEABLE ON THE PERIPHERAL MARGIN OF SAID CELLULARBOTTOM TRAY, AND WHEREIN A PLURALITY OF CELLS ARE FORMED ABOUTVERTICALLY EXTENDING HOLLOW POST INTEFRAL WITH SAID CELLULAR BOTTOM TRAYAND PROJECTING VERTICALLY ABOVE THE PERIPHERAL MARGIN THEREOF, SAIDMETHOD COMPRISING THE FOLLOWING STEPS: (A) SUCKING A PULP FIBER PREFORMFORMATION FOR A PULP SLURRY ONTO A FORAMINOUS DIE OF THE GENERAL SHAPEAND CONTOUR OF SAID EGG CARTON INCLUDING SAID HOLLOW-POST FORMINGPORTIONS; (B) REMOVING SAID PULP FIBER PREFORM FORMATION FROM SAIDFORAMINOUS DIE; (C) DRYING SAID PULP FIBER PREFORM FORMATION AFTERHAVING REMOVED IT FROM SAID FORAMINOUS DIE; AND (D) PRESSING SAID PULPFIBER PREFORM FORMATION BETWEEN MATED PRESSING DIES WHICH INCLUDE MALEAND FEMALE HOLLOW-POST ACCOMMODATING PORTIONS SMALLER IN HORIZONTALCROSS SECTION NEAR THE TOP THEREOF THAN THE CORRESPONDING HORIZONTALCROSS SECTION OF SAID FORAMINOUS DIE, AND COMPACTING AND REFORMING THEPULP FIBER AT THE TOP OF SAID HOLLOW-POST PORTION ON SAID PREFORM ANDREDUCING THE OUTER AND INNER MARGINS OF A TRANSVERSE SECTION NEAR THETOP OF SAID HOLLOWPOST FORMING PORTION.